Conventionally, in a finder of a single lens reflex camera, a focal plane on which a real image is formed is observed, and the real image formed by an objective lens is diffused using the focal plane as a diffusing surface, and diffused light which enters into a photometric device positioned near an ocular is measured.
FIG. 8 shows a configuration example thereof, where when a field of view is observed, an image of an object is formed on a focal plane 53 on a reticle by an objective lens 51, and this image is observed by an eye point EP (human eyes) via a penta prism and an ocular, which are not illustrated. In such a finder, a Fresnel lens 54 plays a role of condensing light transmitted through an exit pupil 52 of the object lens 51. A photometric device 55 is positioned near the ocular so that an optical axis thereof is inclined from an optical axis of the finder (ocular), and photometry is performed by condensing a part of the rays which are condensed at the eye point EP, to the photometric device 55.
As a camera having this type of configuration, a camera of which diffusion characteristic of the focal plane is designed to be asymmetric, so as to secure sufficient light for the photometric device is known (e.g. see Japanese Patent Publication No. H1-36088).